Changes in Antioxidant and Photosynthetic Capacity in Rice Under Different Substrates

Against the backdrop of a changing global climate, the soil environment may undergo significant changes, directly affecting agricultural productivity and exacerbating global food security issues. Three different substrates were set up in this study, namely, S (high sand and low nutrient content), T (medium sand and medium nutrient content), and TT (low sand and high nutrient content). The results showed that the root/shoot ratio increased as the sand content increased (nutrient content decreased). Rice in different substrates had various degrees of dependence on antioxidant enzymes and antioxidants. For example, seedlings in TT treatment may depend more on ascorbic acid (AsA) compared to T. In addition, compared with S and T, the photosynthetic activity of rice in the optimized substrate (TT) was the highest; the net photosynthetic rate (Pn) of TT seedlings was significantly higher than that of T. This study also detected that the change in substrates affected the gas exchange parameters of rice leaves. The transpiration rate (Tr) and stomatal conductance (Gs) of the TT treatment were higher than those of the T treatment. The results of this study may provide a scientific basis for formulating agricultural management strategies.